Imagine a scenario where you take out leftover food and throw it away, and a volunteer in front of the bucket tells you to separate waste. If you have two options, one is to do it by yourself, and the other is that you do not sort or even give the waste to the volunteer for separation. If the volunteer were a stranger, which one would you choose? If the volunteer were an acquaintance, which one would you choose?

Although the growing waste threatens human well-being and environment, the participation rates of waste separation and recycling remain low without the monitoring from volunteers. In the absence of improved laws and regulations, residents are reluctant to cooperate with volunteers in waste separation. The study focused on one key issue urgently to be resolved for effective waste separation. Which types of volunteers (familiar or unfamiliar; older, young adults or children) are more effective in promoting cooperation between residents and volunteers?

To address this issue, Dr. Pingping Liu and Xuan Zhang in Buxin Han's PI group in the CAS Key Laboratory of Mental Health conducted an experimental study. Through three experiments and one qualitative interview, the researchers investigated the effects of familiarity and age on residents' cooperation, as well as the mediating roles of reputational concern and social distance.

The findings show that familiarity strongly promoted cooperation. People cooperated more with the high familiar volunteers than with the low familiar or strange volunteers (see Figure 1). As age and familiarity interacting to affect the cooperative intention, participants cooperated more with older volunteers in the low familiar condition.

 Figure 1. Cooperative attitudes of participants separating waste as a function of familiarity and types of volunteers in the (a) current and (b) next time situation. Image by Dr. LIU Pingping. Note: Error bars represent standard errors; * p < 0.05, *** p < 0.001. 

When social distance and reputational concern were simultaneously treated as mediators in the multiple mediation models, the indirect effect of social distance and reputational concern was significant (see Figure 2). Social distance and reputational concern play a serial mediating role in the effect of familiarity on cooperation.
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Figure 2. The mediating role of reputational concern and social distance during familiarity promoting cooperation. Image by Dr. LIU Pingping.

The researchers firstly suggest the causal relationship between familiarity with volunteers and residents' cooperation in the field of waste separation. The findings demonstrate that helping residents to become familiar with volunteers in advance or recruiting people who are familiar with residents as volunteers, could promote waste separation and help residents form this habit. Social distance and reputational concern play a serial mediating role in the effect of familiarity on cooperation. This study provides suggestions and scientific support for the practice of waste separation and saving management costs.

This study entitled “Familiarity Promotes Resident Cooperation with Volunteers in Waste Separation” has been published on May 12,  2023 in Acta Psychologica Sinica.

This research was supported by the National Natural Science Foundation of China, the Scientific Foundation of the Institute of Psychology, Chinese Academy of Sciences, and the joint program of the Chinese Academy of Sciences and the Japan Society for the Promotion of Science.

LIU Chen
Institute of Psychology Chinese Academy of Sciences
Beijing 100101, China.
E-mail: liuc@psych.ac.cn